Thrombopoietin stimulates migration and activates multiple signaling pathways in hepatoblastoma cells.

Thrombopoietin (TPO), a cytokine that participates in the differentiation and maturation of megakaryocytes, is produced in the liver, but only limited information is available on the biological response of liver-derived cells to TPO. In this study, we investigated whether HepG2 cells express c-Mpl, the receptor for TPO, and whether TPO elicits biological responses and intracellular signaling in this cell type. Specific transcripts for c-Mpl were detected in HepG2 cells by RT-PCR, and expression of the protein was demonstrated by Western blot analysis and immunofluorescence.

Thiazolidinedione treatment inhibits bile duct proliferation and fibrosis in a rat model of chronic cholestasis.

Aim: To investigate the effects of troglitazone (TGZ), an anti-diabetic drug which activates peroxisome proliferator-activated receptor-gamma (PPAR-gamma), for liver tissue repair, and the development of ductular reaction, following common bile duct ligation (BDL) in rats.

Methods: Rats were supplemented with TGZ (0.2% w/w in the pelleted food) for 1 wk before BDL or sham operation.

4-Hydroxynonenal as a selective pro-fibrogenic stimulus for activated human hepatic stellate cells.

Background/aims: 4-Hydroxynonenal (HNE) is a putative pro-fibrogenic product of oxidative stress able to elicit apoptosis and cytotoxicity in several cell types. This study has been performed to evaluate its 'in vivo' levels in injured liver and whether HNE may induce apoptosis and/or affect selected phenotypic responses in activated human hepatic stellate cells (HSC/MF).

Methods/results: During the development of acute liver injury induced by CCl(4), liver tissue HNE levels were in the range 0.

H2O2 and 4-hydroxynonenal mediate amyloid beta-induced neuronal apoptosis by activating JNKs and p38MAPK.

Amyloid beta peptides (Abeta) may be neurotoxic during the progression of Alzheimer's disease by eliciting oxidative stress. Exposure of neuronally differentiated SK-N-BE cells to Abeta(25-35) fragment as well as to full-length Abeta(1-40) and Abeta(1-42) induces early and time-dependent generation of oxidative stress that has been evaluated by carefully monitoring generation of hydrogen peroxide (H(2)O(2)), 4-hydroxynonenal (HNE), thiobarbituric acid reactive substances (TBARS), and fluorescent chromolipids. Abeta treatment also results in the activation of c-Jun aminoterminal kinases (JNKs) and p38(MAPK) and is followed by characteristic nuclear changes of apoptosis as evaluated by DAPI staining and TUNEL technique.

Dehydroepiandrosterone modulates nuclear factor-kappaB activation in hippocampus of diabetic rats.

Oxidative stress induced by chronic hyperglycemia contributes to cerebrovascular complications in diabetes. Reactive oxygen species activate the transcription factor nuclear factor-kappaB (NF-kappaB), which in turn activates a variety of target genes linked to the development of diabetic complications. Dehydroepiandrosterone, an adrenal steroid, which possesses a multitargeted antioxidant effects, is also synthesized de novo by the brain.